In photography, there has been recognized the need for providing flash illumination, at an angle that is suited to the scene coverage of a zoom lens. A zoom lens is capable of a variable range of focus from telephoto to wide-angle settings. Improved image quality may result if the flash illumination angle or spread about the center optical axis of the flash is adjusted to correspond to the scene coverage angle. Thus, at the telephoto setting the flash illumination should be well collimated, while at the wide-angle setting, the flash illumination should be spread over a relatively wide angle about the center axis. In such a camera apparatus, the flash itself may have a variable focus lens that is controlled in response to the focus setting of the zoom lens. This may also be described as a flash beam focuser, which focuses the light from the flash into a smaller or a larger area at the center of the frame (center axis of the flash).
Yet another flash-based technique that may be used to improve image picture quality in certain situations is to vary the power of the camera flash. Somewhat similar to the flash beam focusing technique described above, a variable flash power mechanism may be used to, for example, decrease the light output of the flash when exposure needs to be decreased (due to the flash being too bright). This technique is similar to the flash beam focuser in that it does not shift the angle of the peak of the spatial energy profile of the flash, relative to the center optical axis of the flash.